Capecitabine and Pegylated Interferon Alfa-2a in Treating Patients With Recurrent or Progressive Brain Metastases Due to Breast Cancer

DISEASE CHARACTERISTICS:

Histologically or cytologically confirmed breast cancer that metastasized to the brain, meeting all of the following criteria:

Must have ≥ 1 inoperable brain metastases, meeting 1 of the following criteria:

Progressive or recurrent disease after prior whole-brain or stereotactic radiotherapy
Ineligible for OR unwilling to be treated with radiotherapy
At least 1 unidimensionally measurable brain metastasis by enhanced MRI within the past 21 days
No progression or development of central nervous system (CNS) metastasis during prior treatment with capecitabine, fluorouracil, interferon alfa, or interferon beta

Systemic (i.e., outside the CNS system) cancer must be stable

No progressive disease (e.g., liver, lymphangitic, or lung metastases)

Hormone receptor status:

Not specified

PATIENT CHARACTERISTICS:

Age

18 and over

Sex

Male or female

Menopausal status

Not specified

Performance status

Karnofsky 70-100%

Life expectancy

More than 12 weeks

Hematopoietic

Absolute neutrophil count ≥ 1,500/mm^3
Platelet count ≥ 100,000/mm^3
Hemoglobin ≥ 10 mg/dL
No history of idiopathic thrombocytopenic purpura
No known uncontrolled coagulopathy
No increased risk for anemia (e.g., thalassemia or spherocytosis)
No medically problematic anemia

Hepatic

aspartate aminotransferase (AST or SGOT) and alanine aminotransferase (ALT or SGPT) ≤ 2.5 times upper limit of normal (ULN) (5 times ULN for patients with concurrent liver metastases )
Bilirubin ≤ 1.5 times ULN
Alkaline phosphatase ≤ 2.5 times ULN (5 times ULN for patients with concurrent liver metastases; 10 times ULN for patients with concurrent bone metastases)

Renal

Creatinine ≤ 1.5 times ULN OR
Creatinine clearance ≥ 30 mL/min

Cardiovascular

No congestive heart failure
No symptomatic coronary artery disease
No medically uncontrolled arrhythmia
No other clinically significant cardiac disease
No myocardial infarction within the past 12 months

Gastrointestinal

No history of inflammatory bowel disease
Must have intact upper gastrointestinal tract
Able to swallow tablets
No malabsorption syndrome
No history of gastrointestinal bleeding

Immunologic

No prior unanticipated severe reaction to fluoropyrimidine therapy, interferon, pegylated interferon, or a pegylated moiety
No known sensitivity to fluorouracil
No serious uncontrolled infection
No history of immunologically mediated disease

Other

Not pregnant or nursing
Negative pregnancy test
Fertile patients must use effective contraception during and for 6 months after completion of study treatment
No known dihydropyrimidine dehydrogenase deficiency
No history of depression characterized by a suicide attempt
No history of hospitalization for psychiatric disease
No history of other severe psychiatric disease
No prior disability as a result of psychiatric disease
No history of clinically significant psychiatric disability that would preclude study compliance
No other malignancy within the past 5 years except cured nonmelanoma skin cancer or treated carcinoma in situ of the cervix
No uncontrolled thyroid dysfunction (e.g., thyroid-stimulating hormone not in normal range)
No evidence of severe retinopathy (e.g., Cytomegalovirus (CMV) retinitis or macular degeneration)
No clinically relevant ophthalmologic disorders due to diabetes or hypertension
No other serious uncontrolled medical conditions that would preclude study participation

PRIOR CONCURRENT THERAPY:

Biologic therapy

See Disease Characteristics
At least 3 months since prior interferon alfa or interferon beta

Chemotherapy

See Disease Characteristics
At least 3 months since prior capecitabine or fluorouracil

Endocrine therapy

Concurrent hormonal agents (e.g., tamoxifen, raloxifene, or anastrazole) for breast cancer allowed

Radiotherapy

See Disease Characteristics

Surgery

More than 4 weeks since prior major surgery and recovered

Other

More than 4 weeks since prior participation in another investigational drug study
At least 4 weeks since prior and no concurrent brivudine or sorivudine
No concurrent cimetidine
No other concurrent investigational or commercial agents or therapies for this malignancy